xref: /linux/drivers/iio/adc/ad7768-1.c (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Analog Devices AD7768-1 SPI ADC driver
4  *
5  * Copyright 2017 Analog Devices Inc.
6  */
7 #include <linux/bitfield.h>
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/regulator/consumer.h>
16 #include <linux/sysfs.h>
17 #include <linux/spi/spi.h>
18 
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/trigger.h>
23 #include <linux/iio/triggered_buffer.h>
24 #include <linux/iio/trigger_consumer.h>
25 
26 /* AD7768 registers definition */
27 #define AD7768_REG_CHIP_TYPE		0x3
28 #define AD7768_REG_PROD_ID_L		0x4
29 #define AD7768_REG_PROD_ID_H		0x5
30 #define AD7768_REG_CHIP_GRADE		0x6
31 #define AD7768_REG_SCRATCH_PAD		0x0A
32 #define AD7768_REG_VENDOR_L		0x0C
33 #define AD7768_REG_VENDOR_H		0x0D
34 #define AD7768_REG_INTERFACE_FORMAT	0x14
35 #define AD7768_REG_POWER_CLOCK		0x15
36 #define AD7768_REG_ANALOG		0x16
37 #define AD7768_REG_ANALOG2		0x17
38 #define AD7768_REG_CONVERSION		0x18
39 #define AD7768_REG_DIGITAL_FILTER	0x19
40 #define AD7768_REG_SINC3_DEC_RATE_MSB	0x1A
41 #define AD7768_REG_SINC3_DEC_RATE_LSB	0x1B
42 #define AD7768_REG_DUTY_CYCLE_RATIO	0x1C
43 #define AD7768_REG_SYNC_RESET		0x1D
44 #define AD7768_REG_GPIO_CONTROL		0x1E
45 #define AD7768_REG_GPIO_WRITE		0x1F
46 #define AD7768_REG_GPIO_READ		0x20
47 #define AD7768_REG_OFFSET_HI		0x21
48 #define AD7768_REG_OFFSET_MID		0x22
49 #define AD7768_REG_OFFSET_LO		0x23
50 #define AD7768_REG_GAIN_HI		0x24
51 #define AD7768_REG_GAIN_MID		0x25
52 #define AD7768_REG_GAIN_LO		0x26
53 #define AD7768_REG_SPI_DIAG_ENABLE	0x28
54 #define AD7768_REG_ADC_DIAG_ENABLE	0x29
55 #define AD7768_REG_DIG_DIAG_ENABLE	0x2A
56 #define AD7768_REG_ADC_DATA		0x2C
57 #define AD7768_REG_MASTER_STATUS	0x2D
58 #define AD7768_REG_SPI_DIAG_STATUS	0x2E
59 #define AD7768_REG_ADC_DIAG_STATUS	0x2F
60 #define AD7768_REG_DIG_DIAG_STATUS	0x30
61 #define AD7768_REG_MCLK_COUNTER		0x31
62 
63 /* AD7768_REG_POWER_CLOCK */
64 #define AD7768_PWR_MCLK_DIV_MSK		GENMASK(5, 4)
65 #define AD7768_PWR_MCLK_DIV(x)		FIELD_PREP(AD7768_PWR_MCLK_DIV_MSK, x)
66 #define AD7768_PWR_PWRMODE_MSK		GENMASK(1, 0)
67 #define AD7768_PWR_PWRMODE(x)		FIELD_PREP(AD7768_PWR_PWRMODE_MSK, x)
68 
69 /* AD7768_REG_DIGITAL_FILTER */
70 #define AD7768_DIG_FIL_FIL_MSK		GENMASK(6, 4)
71 #define AD7768_DIG_FIL_FIL(x)		FIELD_PREP(AD7768_DIG_FIL_FIL_MSK, x)
72 #define AD7768_DIG_FIL_DEC_MSK		GENMASK(2, 0)
73 #define AD7768_DIG_FIL_DEC_RATE(x)	FIELD_PREP(AD7768_DIG_FIL_DEC_MSK, x)
74 
75 /* AD7768_REG_CONVERSION */
76 #define AD7768_CONV_MODE_MSK		GENMASK(2, 0)
77 #define AD7768_CONV_MODE(x)		FIELD_PREP(AD7768_CONV_MODE_MSK, x)
78 
79 #define AD7768_RD_FLAG_MSK(x)		(BIT(6) | ((x) & 0x3F))
80 #define AD7768_WR_FLAG_MSK(x)		((x) & 0x3F)
81 
82 enum ad7768_conv_mode {
83 	AD7768_CONTINUOUS,
84 	AD7768_ONE_SHOT,
85 	AD7768_SINGLE,
86 	AD7768_PERIODIC,
87 	AD7768_STANDBY
88 };
89 
90 enum ad7768_pwrmode {
91 	AD7768_ECO_MODE = 0,
92 	AD7768_MED_MODE = 2,
93 	AD7768_FAST_MODE = 3
94 };
95 
96 enum ad7768_mclk_div {
97 	AD7768_MCLK_DIV_16,
98 	AD7768_MCLK_DIV_8,
99 	AD7768_MCLK_DIV_4,
100 	AD7768_MCLK_DIV_2
101 };
102 
103 enum ad7768_dec_rate {
104 	AD7768_DEC_RATE_32 = 0,
105 	AD7768_DEC_RATE_64 = 1,
106 	AD7768_DEC_RATE_128 = 2,
107 	AD7768_DEC_RATE_256 = 3,
108 	AD7768_DEC_RATE_512 = 4,
109 	AD7768_DEC_RATE_1024 = 5,
110 	AD7768_DEC_RATE_8 = 9,
111 	AD7768_DEC_RATE_16 = 10
112 };
113 
114 struct ad7768_clk_configuration {
115 	enum ad7768_mclk_div mclk_div;
116 	enum ad7768_dec_rate dec_rate;
117 	unsigned int clk_div;
118 	enum ad7768_pwrmode pwrmode;
119 };
120 
121 static const struct ad7768_clk_configuration ad7768_clk_config[] = {
122 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_8, 16,  AD7768_FAST_MODE },
123 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_16, 32,  AD7768_FAST_MODE },
124 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_32, 64, AD7768_FAST_MODE },
125 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_64, 128, AD7768_FAST_MODE },
126 	{ AD7768_MCLK_DIV_2, AD7768_DEC_RATE_128, 256, AD7768_FAST_MODE },
127 	{ AD7768_MCLK_DIV_4, AD7768_DEC_RATE_128, 512, AD7768_MED_MODE },
128 	{ AD7768_MCLK_DIV_4, AD7768_DEC_RATE_256, 1024, AD7768_MED_MODE },
129 	{ AD7768_MCLK_DIV_4, AD7768_DEC_RATE_512, 2048, AD7768_MED_MODE },
130 	{ AD7768_MCLK_DIV_4, AD7768_DEC_RATE_1024, 4096, AD7768_MED_MODE },
131 	{ AD7768_MCLK_DIV_8, AD7768_DEC_RATE_1024, 8192, AD7768_MED_MODE },
132 	{ AD7768_MCLK_DIV_16, AD7768_DEC_RATE_1024, 16384, AD7768_ECO_MODE },
133 };
134 
135 static const struct iio_chan_spec ad7768_channels[] = {
136 	{
137 		.type = IIO_VOLTAGE,
138 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
139 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
140 		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
141 		.indexed = 1,
142 		.channel = 0,
143 		.scan_index = 0,
144 		.scan_type = {
145 			.sign = 'u',
146 			.realbits = 24,
147 			.storagebits = 32,
148 			.shift = 8,
149 			.endianness = IIO_BE,
150 		},
151 	},
152 };
153 
154 struct ad7768_state {
155 	struct spi_device *spi;
156 	struct regulator *vref;
157 	struct mutex lock;
158 	struct clk *mclk;
159 	unsigned int mclk_freq;
160 	unsigned int samp_freq;
161 	struct completion completion;
162 	struct iio_trigger *trig;
163 	struct gpio_desc *gpio_sync_in;
164 	const char *labels[ARRAY_SIZE(ad7768_channels)];
165 	/*
166 	 * DMA (thus cache coherency maintenance) may require the
167 	 * transfer buffers to live in their own cache lines.
168 	 */
169 	union {
170 		struct {
171 			__be32 chan;
172 			s64 timestamp;
173 		} scan;
174 		__be32 d32;
175 		u8 d8[2];
176 	} data __aligned(IIO_DMA_MINALIGN);
177 };
178 
ad7768_spi_reg_read(struct ad7768_state * st,unsigned int addr,unsigned int len)179 static int ad7768_spi_reg_read(struct ad7768_state *st, unsigned int addr,
180 			       unsigned int len)
181 {
182 	unsigned int shift;
183 	int ret;
184 
185 	shift = 32 - (8 * len);
186 	st->data.d8[0] = AD7768_RD_FLAG_MSK(addr);
187 
188 	ret = spi_write_then_read(st->spi, st->data.d8, 1,
189 				  &st->data.d32, len);
190 	if (ret < 0)
191 		return ret;
192 
193 	return (be32_to_cpu(st->data.d32) >> shift);
194 }
195 
ad7768_spi_reg_write(struct ad7768_state * st,unsigned int addr,unsigned int val)196 static int ad7768_spi_reg_write(struct ad7768_state *st,
197 				unsigned int addr,
198 				unsigned int val)
199 {
200 	st->data.d8[0] = AD7768_WR_FLAG_MSK(addr);
201 	st->data.d8[1] = val & 0xFF;
202 
203 	return spi_write(st->spi, st->data.d8, 2);
204 }
205 
ad7768_set_mode(struct ad7768_state * st,enum ad7768_conv_mode mode)206 static int ad7768_set_mode(struct ad7768_state *st,
207 			   enum ad7768_conv_mode mode)
208 {
209 	int regval;
210 
211 	regval = ad7768_spi_reg_read(st, AD7768_REG_CONVERSION, 1);
212 	if (regval < 0)
213 		return regval;
214 
215 	regval &= ~AD7768_CONV_MODE_MSK;
216 	regval |= AD7768_CONV_MODE(mode);
217 
218 	return ad7768_spi_reg_write(st, AD7768_REG_CONVERSION, regval);
219 }
220 
ad7768_scan_direct(struct iio_dev * indio_dev)221 static int ad7768_scan_direct(struct iio_dev *indio_dev)
222 {
223 	struct ad7768_state *st = iio_priv(indio_dev);
224 	int readval, ret;
225 
226 	reinit_completion(&st->completion);
227 
228 	ret = ad7768_set_mode(st, AD7768_ONE_SHOT);
229 	if (ret < 0)
230 		return ret;
231 
232 	ret = wait_for_completion_timeout(&st->completion,
233 					  msecs_to_jiffies(1000));
234 	if (!ret)
235 		return -ETIMEDOUT;
236 
237 	readval = ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3);
238 	if (readval < 0)
239 		return readval;
240 	/*
241 	 * Any SPI configuration of the AD7768-1 can only be
242 	 * performed in continuous conversion mode.
243 	 */
244 	ret = ad7768_set_mode(st, AD7768_CONTINUOUS);
245 	if (ret < 0)
246 		return ret;
247 
248 	return readval;
249 }
250 
ad7768_reg_access(struct iio_dev * indio_dev,unsigned int reg,unsigned int writeval,unsigned int * readval)251 static int ad7768_reg_access(struct iio_dev *indio_dev,
252 			     unsigned int reg,
253 			     unsigned int writeval,
254 			     unsigned int *readval)
255 {
256 	struct ad7768_state *st = iio_priv(indio_dev);
257 	int ret;
258 
259 	mutex_lock(&st->lock);
260 	if (readval) {
261 		ret = ad7768_spi_reg_read(st, reg, 1);
262 		if (ret < 0)
263 			goto err_unlock;
264 		*readval = ret;
265 		ret = 0;
266 	} else {
267 		ret = ad7768_spi_reg_write(st, reg, writeval);
268 	}
269 err_unlock:
270 	mutex_unlock(&st->lock);
271 
272 	return ret;
273 }
274 
ad7768_set_dig_fil(struct ad7768_state * st,enum ad7768_dec_rate dec_rate)275 static int ad7768_set_dig_fil(struct ad7768_state *st,
276 			      enum ad7768_dec_rate dec_rate)
277 {
278 	unsigned int mode;
279 	int ret;
280 
281 	if (dec_rate == AD7768_DEC_RATE_8 || dec_rate == AD7768_DEC_RATE_16)
282 		mode = AD7768_DIG_FIL_FIL(dec_rate);
283 	else
284 		mode = AD7768_DIG_FIL_DEC_RATE(dec_rate);
285 
286 	ret = ad7768_spi_reg_write(st, AD7768_REG_DIGITAL_FILTER, mode);
287 	if (ret < 0)
288 		return ret;
289 
290 	/* A sync-in pulse is required every time the filter dec rate changes */
291 	gpiod_set_value(st->gpio_sync_in, 1);
292 	gpiod_set_value(st->gpio_sync_in, 0);
293 
294 	return 0;
295 }
296 
ad7768_set_freq(struct ad7768_state * st,unsigned int freq)297 static int ad7768_set_freq(struct ad7768_state *st,
298 			   unsigned int freq)
299 {
300 	unsigned int diff_new, diff_old, pwr_mode, i, idx;
301 	int res, ret;
302 
303 	diff_old = U32_MAX;
304 	idx = 0;
305 
306 	res = DIV_ROUND_CLOSEST(st->mclk_freq, freq);
307 
308 	/* Find the closest match for the desired sampling frequency */
309 	for (i = 0; i < ARRAY_SIZE(ad7768_clk_config); i++) {
310 		diff_new = abs(res - ad7768_clk_config[i].clk_div);
311 		if (diff_new < diff_old) {
312 			diff_old = diff_new;
313 			idx = i;
314 		}
315 	}
316 
317 	/*
318 	 * Set both the mclk_div and pwrmode with a single write to the
319 	 * POWER_CLOCK register
320 	 */
321 	pwr_mode = AD7768_PWR_MCLK_DIV(ad7768_clk_config[idx].mclk_div) |
322 		   AD7768_PWR_PWRMODE(ad7768_clk_config[idx].pwrmode);
323 	ret = ad7768_spi_reg_write(st, AD7768_REG_POWER_CLOCK, pwr_mode);
324 	if (ret < 0)
325 		return ret;
326 
327 	ret =  ad7768_set_dig_fil(st, ad7768_clk_config[idx].dec_rate);
328 	if (ret < 0)
329 		return ret;
330 
331 	st->samp_freq = DIV_ROUND_CLOSEST(st->mclk_freq,
332 					  ad7768_clk_config[idx].clk_div);
333 
334 	return 0;
335 }
336 
ad7768_sampling_freq_avail(struct device * dev,struct device_attribute * attr,char * buf)337 static ssize_t ad7768_sampling_freq_avail(struct device *dev,
338 					  struct device_attribute *attr,
339 					  char *buf)
340 {
341 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
342 	struct ad7768_state *st = iio_priv(indio_dev);
343 	unsigned int freq;
344 	int i, len = 0;
345 
346 	for (i = 0; i < ARRAY_SIZE(ad7768_clk_config); i++) {
347 		freq = DIV_ROUND_CLOSEST(st->mclk_freq,
348 					 ad7768_clk_config[i].clk_div);
349 		len += scnprintf(buf + len, PAGE_SIZE - len, "%d ", freq);
350 	}
351 
352 	buf[len - 1] = '\n';
353 
354 	return len;
355 }
356 
357 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(ad7768_sampling_freq_avail);
358 
ad7768_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long info)359 static int ad7768_read_raw(struct iio_dev *indio_dev,
360 			   struct iio_chan_spec const *chan,
361 			   int *val, int *val2, long info)
362 {
363 	struct ad7768_state *st = iio_priv(indio_dev);
364 	int scale_uv, ret;
365 
366 	switch (info) {
367 	case IIO_CHAN_INFO_RAW:
368 		ret = iio_device_claim_direct_mode(indio_dev);
369 		if (ret)
370 			return ret;
371 
372 		ret = ad7768_scan_direct(indio_dev);
373 		if (ret >= 0)
374 			*val = ret;
375 
376 		iio_device_release_direct_mode(indio_dev);
377 		if (ret < 0)
378 			return ret;
379 
380 		return IIO_VAL_INT;
381 
382 	case IIO_CHAN_INFO_SCALE:
383 		scale_uv = regulator_get_voltage(st->vref);
384 		if (scale_uv < 0)
385 			return scale_uv;
386 
387 		*val = (scale_uv * 2) / 1000;
388 		*val2 = chan->scan_type.realbits;
389 
390 		return IIO_VAL_FRACTIONAL_LOG2;
391 
392 	case IIO_CHAN_INFO_SAMP_FREQ:
393 		*val = st->samp_freq;
394 
395 		return IIO_VAL_INT;
396 	}
397 
398 	return -EINVAL;
399 }
400 
ad7768_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long info)401 static int ad7768_write_raw(struct iio_dev *indio_dev,
402 			    struct iio_chan_spec const *chan,
403 			    int val, int val2, long info)
404 {
405 	struct ad7768_state *st = iio_priv(indio_dev);
406 
407 	switch (info) {
408 	case IIO_CHAN_INFO_SAMP_FREQ:
409 		return ad7768_set_freq(st, val);
410 	default:
411 		return -EINVAL;
412 	}
413 }
414 
ad7768_read_label(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,char * label)415 static int ad7768_read_label(struct iio_dev *indio_dev,
416 	const struct iio_chan_spec *chan, char *label)
417 {
418 	struct ad7768_state *st = iio_priv(indio_dev);
419 
420 	return sprintf(label, "%s\n", st->labels[chan->channel]);
421 }
422 
423 static struct attribute *ad7768_attributes[] = {
424 	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
425 	NULL
426 };
427 
428 static const struct attribute_group ad7768_group = {
429 	.attrs = ad7768_attributes,
430 };
431 
432 static const struct iio_info ad7768_info = {
433 	.attrs = &ad7768_group,
434 	.read_raw = &ad7768_read_raw,
435 	.write_raw = &ad7768_write_raw,
436 	.read_label = ad7768_read_label,
437 	.debugfs_reg_access = &ad7768_reg_access,
438 };
439 
ad7768_setup(struct ad7768_state * st)440 static int ad7768_setup(struct ad7768_state *st)
441 {
442 	int ret;
443 
444 	/*
445 	 * Two writes to the SPI_RESET[1:0] bits are required to initiate
446 	 * a software reset. The bits must first be set to 11, and then
447 	 * to 10. When the sequence is detected, the reset occurs.
448 	 * See the datasheet, page 70.
449 	 */
450 	ret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x3);
451 	if (ret)
452 		return ret;
453 
454 	ret = ad7768_spi_reg_write(st, AD7768_REG_SYNC_RESET, 0x2);
455 	if (ret)
456 		return ret;
457 
458 	st->gpio_sync_in = devm_gpiod_get(&st->spi->dev, "adi,sync-in",
459 					  GPIOD_OUT_LOW);
460 	if (IS_ERR(st->gpio_sync_in))
461 		return PTR_ERR(st->gpio_sync_in);
462 
463 	/* Set the default sampling frequency to 32000 kSPS */
464 	return ad7768_set_freq(st, 32000);
465 }
466 
ad7768_trigger_handler(int irq,void * p)467 static irqreturn_t ad7768_trigger_handler(int irq, void *p)
468 {
469 	struct iio_poll_func *pf = p;
470 	struct iio_dev *indio_dev = pf->indio_dev;
471 	struct ad7768_state *st = iio_priv(indio_dev);
472 	int ret;
473 
474 	mutex_lock(&st->lock);
475 
476 	ret = spi_read(st->spi, &st->data.scan.chan, 3);
477 	if (ret < 0)
478 		goto err_unlock;
479 
480 	iio_push_to_buffers_with_timestamp(indio_dev, &st->data.scan,
481 					   iio_get_time_ns(indio_dev));
482 
483 err_unlock:
484 	iio_trigger_notify_done(indio_dev->trig);
485 	mutex_unlock(&st->lock);
486 
487 	return IRQ_HANDLED;
488 }
489 
ad7768_interrupt(int irq,void * dev_id)490 static irqreturn_t ad7768_interrupt(int irq, void *dev_id)
491 {
492 	struct iio_dev *indio_dev = dev_id;
493 	struct ad7768_state *st = iio_priv(indio_dev);
494 
495 	if (iio_buffer_enabled(indio_dev))
496 		iio_trigger_poll(st->trig);
497 	else
498 		complete(&st->completion);
499 
500 	return IRQ_HANDLED;
501 };
502 
ad7768_buffer_postenable(struct iio_dev * indio_dev)503 static int ad7768_buffer_postenable(struct iio_dev *indio_dev)
504 {
505 	struct ad7768_state *st = iio_priv(indio_dev);
506 
507 	/*
508 	 * Write a 1 to the LSB of the INTERFACE_FORMAT register to enter
509 	 * continuous read mode. Subsequent data reads do not require an
510 	 * initial 8-bit write to query the ADC_DATA register.
511 	 */
512 	return ad7768_spi_reg_write(st, AD7768_REG_INTERFACE_FORMAT, 0x01);
513 }
514 
ad7768_buffer_predisable(struct iio_dev * indio_dev)515 static int ad7768_buffer_predisable(struct iio_dev *indio_dev)
516 {
517 	struct ad7768_state *st = iio_priv(indio_dev);
518 
519 	/*
520 	 * To exit continuous read mode, perform a single read of the ADC_DATA
521 	 * reg (0x2C), which allows further configuration of the device.
522 	 */
523 	return ad7768_spi_reg_read(st, AD7768_REG_ADC_DATA, 3);
524 }
525 
526 static const struct iio_buffer_setup_ops ad7768_buffer_ops = {
527 	.postenable = &ad7768_buffer_postenable,
528 	.predisable = &ad7768_buffer_predisable,
529 };
530 
531 static const struct iio_trigger_ops ad7768_trigger_ops = {
532 	.validate_device = iio_trigger_validate_own_device,
533 };
534 
ad7768_regulator_disable(void * data)535 static void ad7768_regulator_disable(void *data)
536 {
537 	struct ad7768_state *st = data;
538 
539 	regulator_disable(st->vref);
540 }
541 
ad7768_set_channel_label(struct iio_dev * indio_dev,int num_channels)542 static int ad7768_set_channel_label(struct iio_dev *indio_dev,
543 						int num_channels)
544 {
545 	struct ad7768_state *st = iio_priv(indio_dev);
546 	struct device *device = indio_dev->dev.parent;
547 	const char *label;
548 	int crt_ch = 0;
549 
550 	device_for_each_child_node_scoped(device, child) {
551 		if (fwnode_property_read_u32(child, "reg", &crt_ch))
552 			continue;
553 
554 		if (crt_ch >= num_channels)
555 			continue;
556 
557 		if (fwnode_property_read_string(child, "label", &label))
558 			continue;
559 
560 		st->labels[crt_ch] = label;
561 	}
562 
563 	return 0;
564 }
565 
ad7768_probe(struct spi_device * spi)566 static int ad7768_probe(struct spi_device *spi)
567 {
568 	struct ad7768_state *st;
569 	struct iio_dev *indio_dev;
570 	int ret;
571 
572 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
573 	if (!indio_dev)
574 		return -ENOMEM;
575 
576 	st = iio_priv(indio_dev);
577 	st->spi = spi;
578 
579 	st->vref = devm_regulator_get(&spi->dev, "vref");
580 	if (IS_ERR(st->vref))
581 		return PTR_ERR(st->vref);
582 
583 	ret = regulator_enable(st->vref);
584 	if (ret) {
585 		dev_err(&spi->dev, "Failed to enable specified vref supply\n");
586 		return ret;
587 	}
588 
589 	ret = devm_add_action_or_reset(&spi->dev, ad7768_regulator_disable, st);
590 	if (ret)
591 		return ret;
592 
593 	st->mclk = devm_clk_get_enabled(&spi->dev, "mclk");
594 	if (IS_ERR(st->mclk))
595 		return PTR_ERR(st->mclk);
596 
597 	st->mclk_freq = clk_get_rate(st->mclk);
598 
599 	mutex_init(&st->lock);
600 
601 	indio_dev->channels = ad7768_channels;
602 	indio_dev->num_channels = ARRAY_SIZE(ad7768_channels);
603 	indio_dev->name = spi_get_device_id(spi)->name;
604 	indio_dev->info = &ad7768_info;
605 	indio_dev->modes = INDIO_DIRECT_MODE;
606 
607 	ret = ad7768_setup(st);
608 	if (ret < 0) {
609 		dev_err(&spi->dev, "AD7768 setup failed\n");
610 		return ret;
611 	}
612 
613 	st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
614 					  indio_dev->name,
615 					  iio_device_id(indio_dev));
616 	if (!st->trig)
617 		return -ENOMEM;
618 
619 	st->trig->ops = &ad7768_trigger_ops;
620 	iio_trigger_set_drvdata(st->trig, indio_dev);
621 	ret = devm_iio_trigger_register(&spi->dev, st->trig);
622 	if (ret)
623 		return ret;
624 
625 	indio_dev->trig = iio_trigger_get(st->trig);
626 
627 	init_completion(&st->completion);
628 
629 	ret = ad7768_set_channel_label(indio_dev, ARRAY_SIZE(ad7768_channels));
630 	if (ret)
631 		return ret;
632 
633 	ret = devm_request_irq(&spi->dev, spi->irq,
634 			       &ad7768_interrupt,
635 			       IRQF_TRIGGER_RISING | IRQF_ONESHOT,
636 			       indio_dev->name, indio_dev);
637 	if (ret)
638 		return ret;
639 
640 	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
641 					      &iio_pollfunc_store_time,
642 					      &ad7768_trigger_handler,
643 					      &ad7768_buffer_ops);
644 	if (ret)
645 		return ret;
646 
647 	return devm_iio_device_register(&spi->dev, indio_dev);
648 }
649 
650 static const struct spi_device_id ad7768_id_table[] = {
651 	{ "ad7768-1", 0 },
652 	{}
653 };
654 MODULE_DEVICE_TABLE(spi, ad7768_id_table);
655 
656 static const struct of_device_id ad7768_of_match[] = {
657 	{ .compatible = "adi,ad7768-1" },
658 	{ }
659 };
660 MODULE_DEVICE_TABLE(of, ad7768_of_match);
661 
662 static struct spi_driver ad7768_driver = {
663 	.driver = {
664 		.name = "ad7768-1",
665 		.of_match_table = ad7768_of_match,
666 	},
667 	.probe = ad7768_probe,
668 	.id_table = ad7768_id_table,
669 };
670 module_spi_driver(ad7768_driver);
671 
672 MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
673 MODULE_DESCRIPTION("Analog Devices AD7768-1 ADC driver");
674 MODULE_LICENSE("GPL v2");
675